Introduction:
When it comes to revising a subject, there are various methods available, including online quizzes and offline practice tests. Both approaches have their own advantages and disadvantages. In this response, we will explore the benefits and drawbacks of each method to help you make an informed decision.

Online quizzes:
- Convenient: Online quizzes can be accessed anytime and anywhere as long as you have an internet connection. This flexibility allows you to revise the subject at your own pace and convenience.
- Immediate feedback: Online quizzes often provide immediate feedback, allowing you to identify your strengths and weaknesses in real-time. This feedback can help you focus on areas that require further attention.
- Variety of questions: Online quizzes usually offer a wide range of questions, covering different topics and difficulty levels. This diversity can expose you to various concepts and help you develop a comprehensive understanding of the subject.
- Time management: Online quizzes often have time limits, which can help you practice managing your time effectively, a crucial skill for competitive exams like UPSC.
- Limited context: Online quizzes may lack the context that offline practice tests provide. They often focus solely on questions and answers, without providing the broader context of the subject matter.
- Potential distractions: Online quizzes may be prone to distractions, such as notifications from other applications or websites. It is important to create a distraction-free environment to maximize the effectiveness of online revision.

Offline practice tests:
- Comprehensive understanding: Offline practice tests typically provide a more comprehensive understanding of the subject as they often include detailed explanations and solutions. This can be particularly helpful for complex topics.
- Mimicking exam conditions: Offline practice tests can simulate exam conditions, allowing you to experience the pressure and time constraints that you will encounter during the actual exam. This can help you develop resilience and improve your performance under stress.
- No internet dependency: Unlike online quizzes, offline practice tests do not require an internet connection, ensuring uninterrupted revision sessions.
- Limited accessibility: Offline practice tests may not be easily accessible to everyone, especially those who do not have access to study materials or a printing facility.
- Less variety: Offline practice tests may have a limited number of questions compared to online quizzes, which may limit the exposure to different concepts and question types.

Conclusion:
Choosing between online quizzes and offline practice tests for revising a subject is subjective and depends on personal preferences and circumstances. Both methods have their own merits and drawbacks. It is recommended to utilize a combination of both approaches to reap the benefits of comprehensive understanding, immediate feedback, time management, and exposure to various question types. Remember to create a conducive learning environment and stay focused on your revision goals.